The rarity and deeply embedded nature of stars with masses larger than 8 solar masses has limited our understanding of their formation. Previous work has shown that complementing spectral energy distributions with interferometric and imaging data can probe the circumstellar environments of massive young stellar objects (MYSOs) well. However, complex studies of single objects often use different approaches in their analysis. Therefore the results of these studies cannot be directly compared. This work aims to obtain the physical characteristics of a sample of MYSOs at ~0.01" scales, at 0.1" scales, and as a whole, which enables us to compare the characteristics of the sources. We apply the same multi-scale method and analysis to a sample of MYSOs. High-resolution interferometric data, near-diffraction-limited imaging data, and a multi-wavelength spectral energy distribution are combined. By fitting simulated observables derived from 2.5D radiative transfer models of disk-outflow-envelope systems to our observations, the properties of the MYSOs are constrained. We find that the observables of all the MYSOs can be reproduced by models with disk-outflow-envelope geometries, analogous to the Class I geometry associated with low-mass protostars. The characteristics of the envelopes and the cavities within them are very similar across our sample. On the other hand, the disks seem to differ between the objects, in particular with regards to what we interpret as evidence of complex structures and inner holes. This is comparable to the morphologies observed for low-mass young stellar objects. A strong correlation is found between the luminosity of the central MYSO and the size of the transition disk-like inner hole for the MYSOs, implying that photoevaporation or the presence of binary companions may be the cause.
Unveiling the Milky Way with a Gaia DR3 census of OB-type stars within 2 kpc. I. Tracing local Galactic structure, massive star-forming regions and core-collapse supernova progenitors
Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CY Cergy Paris Université, CNRS(巴黎天文台,巴黎文理研究大学,索邦大学,巴黎西岱大学,CY塞吉-蓬图瓦兹大学,法国国家科学研究中心);Max-Planck-Institut für Astronomie(马克斯·普朗克天文学研究所);INAF – Osservatorio Astrofisico di Torino(意大利国家天体物理研究所都灵天文台);University of Vienna(维也纳大学);Keele University(基尔大学);Instituto de Astrofísica de Canarias(加那利天体物理学研究所);Universidad de La Laguna(拉古纳大学);European Southern Observatory(欧洲南方天文台)
A JWST, ALMA and VLA survey of the Ophiuchus-A star-forming region: Unveiling hidden dust mass and connecting infrared outflows to their radio origins
University of Leeds(利兹大学);Universitat de Barcelona(巴塞罗那大学);Institut d’Estudis Espacials de Catalunya(加泰罗尼亚空间研究所);National Sun Yat-Sen University(国立中山大学);National Taiwan Normal University(国立台湾师范大学);Jet Propulsion Laboratory, California Institute of Technology(加州理工学院喷气推进实验室)
Unveiling Stellar Feedback and Cloud Structure in the $ρ$ Ophiuchi A Region with ALMA and JWST: Discovery of Substellar Cores, C$^{18}$O Striations, and Protostellar Outflows
模糊和混乱合在一起限制了我们对银河系内部的了解。即使在中等距离,恒星系统的识别也会因背景源的密度极高而变得复杂。在这里,我们提供了一个非常揭示这些复杂性的例子,揭示了一个巨大的,巨大的,年轻的星团在人马座臂,一直逃脱检测到现在,尽管包含30多颗恒星比$G=13$亮。结合Gaia DR 2天体测量、Gaia和2 MASS测光和光谱学,我们发现这个位于$\sim2.3\:$ kpc的新星团,我们将其命名为Valparaiso 1,年龄约75 Ma,包含大量的演化恒星,其中我们重点介绍了4d经典造父变星CM Sct和一颗M型巨星,这可能是在银河系年轻疏散星团中首次发现AGB星。虽然强烈的微分红化使得精确的参数确定不可行,直接比较类似年龄的星团表明,瓦尔帕莱索~1是太阳邻域中质量最大的星团之一,初始质量接近$10^{4}\:$ M $_{\odot}$。
ALMA's sharpest view of IRAS 08544-4431: Unveiling the dust distribution asymmetries in the circumbinary disk
Macquarie University(麦考瑞大学);INAF, Osservatorio Astronomico di Roma(意大利国家天体物理研究所罗马天文台);ATNF, CSIRO, Space and Astronomy(澳大利亚联邦科学与工业研究组织空间与天文部射电天文国家设施);KU Leuven(荷语鲁汶大学)
The Persistent Radio Sources and Multi-wavelength Counterparts of Fast Radio Bursts in Massive Binary Systems
School of Astronomy and Space Science, Nanjing University(南京大学天文与空间科学学院);Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education(教育部现代天文与天体物理重点实验室(南京大学));Department of Astronomy, School of Physical Sciences, University of Science and Technology of China(中国科学技术大学物理学院天文学系)
Extended stellar systems in the solar neighborhood. IV. Meingast 1: the most massive stellar stream in the solar neighborhood
附近的恒星流携带着关于银河系恒星系统动力学演化和破裂、盘内质量分布的独特信息,为行星形成和演化研究提供了独特的目标。我们重新审视了Meingast等人(2019)发现的流,使用Gaia DR2数据和机器学习方法搜索新成员。我们使用一类支持向量机的装袋分类器进行搜索的新的流成员的位置和适当的运动。我们使用可变的预测频率,从众多的分类器来估计流成员资格标准,我们使用它来选择高保真源。我们使用HR图和笛卡尔速度分布作为测试和验证工具。我们发现了大约2000个高保真的流成员,或者比以前已知的多一个数量级,揭示了整个恒星质量谱中的流人口,从B星到M星,包括白矮星。我们发现,除了稍微更贫金属,流的HRD是无法区分的,从昴星团。对于我们最完整的质量范围,$\sim$ 0.2 M $_\odot$ $ < $ M $ < $ $\sim$ 4 M $_\odot$,我们发现一个正常的IMF,使我们能够估计流的总质量约为2000 M $_\odot$,使这个相对年轻的流迄今为止已知的最大质量。此外,我们确定了几个白矮星作为潜在的流成员。附近的Meingast 1流,由于其丰富,年龄和距离,是一个新的基本实验室恒星和行星形成和演化研究的研究不足的重力无约束恒星形成模式。我们还证明了单类支持向量机可以有效地用于揭示附近恒星系统的全部恒星星族与盖亚数据。